Health Encyclopedia

Viral Gastroenteritis

What is viral gastroenteritis?

Viral gastroenteritis is an inflammation, swelling, and irritation of the inside lining of your gastrointestinal tract. A virus causes this illness. It can infect your stomach, small intestine, and large intestine.

Viral gastroenteritis is very common. In most cases, it lasts only a few days and doesn’t require treatment. The biggest danger is dehydration from loss of fluid due to diarrhea and vomiting.

What causes viral gastroenteritis?

Several viruses can cause gastroenteritis. Viruses can be found in the vomit and the diarrhea of infected people. It can live for a long time outside the body. People who are infected can spread the virus to objects they touch, especially if they don’t wash their hands after using the bathroom. Food workers with the infection can spread it to others through food and beverages. Sewage that gets into the water supply can also spread the illness. Although viral gastroenteritis is sometimes called "stomach flu," the seasonal influenza (flu) virus does not cause it.

Some of the common viruses that cause gastroenteritis include:

Rotavirus. This virus most commonly infects infants age 3 to 15 months. The illness lasts for 3 to 7 days and is most common in fall and winter.

Norovirus. This is the most common cause of adult infections and the virus that’s usually responsible for outbreaks on cruise ships. Symptoms last from 1 to 3 days and can occur any time of the year.

Adenovirus. This virus occurs year-round and affects children under age 2. Symptoms last from 5 to 12 days.

Many other viruses can also cause viral gastroenteritis.

What are the symptoms of viral gastroenteritis?

Symptoms of viral gastroenteritis usually begin about 1 to 2 days after the virus gets into the body.

Common symptoms include:

Nausea

Vomiting

Watery diarrhea

Other possible symptoms are:

Headache

Fever

Chills

Stomachache

Signs of dehydration:

Decreased urine output

Dark-colored urine

Dry skin

Thirst

Dizziness

Signs of dehydration in young children:

Dry diapers (from a lack of urination)

Lack of tears

Dry mouth

Drowsiness

Sunken fontanel (the soft spot on the top of an infant’s head)

How is viral gastroenteritis diagnosed?

Your healthcare provider will most likely diagnose your condition based on your history and symptoms. You will rarely need testing. If your symptoms persist, your healthcare provider may ask for a stool sample to look for viruses, bacteria, and parasites.

Can viral gastroenteritis be prevented?

Vaccines are available to protect children from rotavirus. Healthcare providers give shots to babies before age 6 months. You and your children can help prevent viral gastroenteritis by taking these steps:

Wash hands for 20 seconds with soap and water after going to the bathroom, after changing a diaper, and before touching any food.

Use alcohol-based sanitizers.

If someone in the house has gastroenteritis, wash all surfaces that might be contaminated with a bleach-based cleaner.

Don't eat or drink any food or water with warnings of contamination.

How is viral gastroenteritis treated?

Specific treatment is usually not needed. In most cases, you simply need to drink plenty of fluids and rest at home until the virus leaves your system. In rare cases, you may need treatment for severe dehydration, with IV (intravenous) fluids.

Helpful home care tips include:

Drink plenty of light fluids like water, ice chips, fruit juice, and broth. Keep in mind that sports drinks are high in sugar and are not appropriate if you are extremely dehydrated. In this case, you will need an oral rehydration solution.

Don't have drinks that contain milk, caffeine, or alcohol.

Once you feel hungry again, start with mild, easy to digest foods.

Rehydrate children with oral rehydration solutions.

You may take antidiarrheal medicines for a couple days. But don't take these if you have a fever or bloody stool. Don't take them if you are an elderly adult.. Don't give these to a child.

When should I call my healthcare provider?

Viral gastroenteritis is common in children and adults. In most cases, the disease is not serious and will run its course in a few days. Call your healthcare provider if you or a family member has vomiting or diarrhea that’s not getting better, if you see blood or tar-like stool, or if you have any signs of dehydration.

Key points about viral gastroenteritis

Viral gastroenteritis is an inflammation of the inside lining of your gastrointestinal tract.

It can be caused by rotavirus, norovirus, adenovirus, and other viruses.

Babies can be vaccinated against rotavirus.

Symptoms of viral gastroenteritis are nausea, vomiting, and watery diarrhea.

Dehydration is the most serious complication of this illness.

This illness should run its course in a few days but may need medical attention of diarrhea or vomiting persists or if there are signs of dehydration.

Next steps

Tips to help you get the most from a visit to your healthcare provider:

Know the reason for your visit and what you want to happen.

Before your visit, write down questions you want answered.

Bring someone with you to help you ask questions and remember what your provider tells you.

At the visit, write down the name of a new diagnosis, and any new medicines, treatments, or tests. Also write down any new instructions your provider gives you.

Know why a new medicine or treatment is prescribed, and how it will help you. Also know what the side effects are.

Ask if your condition can be treated in other ways.

Know why a test or procedure is recommended and what the results could mean.

Know what to expect if you do not take the medicine or have the test or procedure.

If you have a follow-up appointment, write down the date, time, and purpose for that visit.

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